高氧和脂多糖诱导人胚肺成纤维细胞NF-κB的动态表达

Lipopolysaccharide and hyperoxia induce nuclear factorkappa B expression in human embryo lung fibroblasts in vitro

摘要:

目的近年研究表明，支气管肺发育不良的发生与宫内炎性因子暴露和出生后机械通气、高氧暴露有着密切的联系。该研究选取人胚肺成纤维细胞，模拟炎性暴露和高氧暴露环境，探讨高氧和脂多糖（lipopolysaccharide，LPS）对人胚肺成纤维细胞核转录因子NFκB表达的影响。方法60%高氧，LPS（100 ng/mL）及两者同时刺激人胚肺成纤维细胞0.5，1，2及4 h，用免疫细胞化学观察其亚基p50及p65的核转位，RTPCR方法检测NFκB p50和p65 mRNA。结果LPS的直接刺激迅速诱导p50及p65的核转位，0.5 h即可致NFκB迅速活化，1 h 达到高峰，后逐渐下降；高氧刺激诱导p50 及p65核转位，1 h达高峰，之后迅速下降；高氧和LPS联合刺激p50及p65亚基核转位，在2 h达高峰，然后缓慢下降。但4 h时活化效应明显高于LPS组和高氧组。结论同时暴露于高氧和LPS组人胚肺成纤维细胞中NFκB的活化比单独暴露因素下活化更为显著，活化持续时间更长，提示暴露于宫内炎性环境中的患儿生后又高氧/辅助通气更容易导致肺部疾病。

Abstract:

ObjectiveThe development of bronchopulmonary dysplasia (BPD) is attributed to intrauterine inflammatory and postnatal mechanical ventilation and hyperoxia. The present study was aimed to investigate the effects of lipopolysaccharide (LPS) and hyperoxia exposure on the nuclear factorkappa B (NFκB) expression in human embryo lung fibroblasts (HELFs) in vitro.MethodsEither LPS (100 ng/mL) or hyperoxia (60%), or a combination of both was employed to stimulate confluent HELFs. After 0.5, 1, 2 and 4 hrs of stimulation, the nuclear translocation of two subunits p50 and p65 in HELFs was detected with immunocytochemistry. Reverse transcription quantitative polymerase chain reaction (RTPCR) was used to measure mRNA expression of NFκB p50 and p65.ResultsLPS or hyperoxia stimulation induced the nuclear translocation of p50 and p65 at 30 minutes of exposure. mRNA expression of NFκB p50 and p65 peaked at 1 hr and then gradually decreased. A stimulation of LPS combined with hyperoxia induced the nuclear translocation of p50 and p65. NFκB p50 and p65 mRNA expression peaked at 2 hrs of stimulation and then decreased slowly, but was significantly higher than that in the LPS or hyperoxia stimulation alone group 4 hrs after stimulation.ConclusionsBoth LPS and hyperoxia exposure induced NFκB activation in the HELFs in vitro. Hyperoxia combined with LPS induced a more prolonged duration of NFκB activation. This suggests that the individuals who were subjected to intrauterine inflammation and postnatal hyperoxia exposure are more vulnerable to lung injury.